Trip-valve gearing



( No Model.) 2 Sheets'-Sheet 1.

W. M. WHITLOGK.

TRIP VALVE GEARING. No. 398,014. Patented Feb. 19, 1889.

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M. WHITLOOK.

TRIP VALVE GEARING.

Patented Feb.- 19.- 1889.

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Mrs STATES PATENT rricn.

\YILBUR M. \VHITLOCK, OF NEIVARK, NEIV JERSEY.

TRIP-VALVE GEARING.

SPECIFICATION forming part of Letters Patent No. 398,014, dated February19, 1889.

Application filed October 11, 1888- Serial No. 287,840. (No model.)

To all whom it may concern..-

Be it known that I, WILBUR M. W HITLOCK, a citizen of the United States,residing at Newark, Essex county, New Jersey, have in vented certain newand useful Improvements in Trip-Valve Gearing, fully described andrepresented in the following specification and the accompanyingdrawings, forming a part of the same.

The object of my invention is to adapt the Corliss valve-motion to usein engines provided with piston-valvcs, and to obviate the use ofseparate stem-chests and separate valves at the two ind uction-ports andthe two eductionports of the cylinder. By my construction a singlesteam-chest is used and two independent balanced piston-valves arearranged and operated to admit the steam to and discharge it from thecylinder with the same effect as the four valves used in the Corlissengine. I employ the same trip-motion and the same governing devices ashave long been used in the Corliss engine, and which are alreadyunderstood, and I connect each of my pistonvalves with an independentlatch for tripping it at-the desired point in the stroke, and rendersuch point variable under the control of the governor, as in otherengines. The valve is actuated by a rock-shaft, with which it has apositive connection, and is formed of two cylindrical heads or pistonsof slightlydift'erent diameters, between which is a space in constantcommunication with the exhaust.

The steam is admitted to the opposite end of each piston-valve tosubstantially balance it, and one of the pistons operates to cut off thesteam from the induction-port, while the other piston serves to compressthe steam in a dashpot or compression-chamber provided for the purposeto produce a reaction and shut off the steam automatically when thevalve is released by the cut-off mechanism at any desired point in thestroke. The larger area upon one end of the valve operates, whenemployed, to develop a resistance to the move ment of the valve when ithas wholly closed the induction-port The invention will be understood byrcferonce to the annexed drawings, in which Figure l is a sideelevation, and Fig. 2 a plan, of a steam-engine cylinder and chestprovided with my attachments. Fig. 3 is a view of the outer side of thechest. Fig. 4 is a longitudinal section of the chest on line a; as inFig. 1. Fig. 5 is a longitudinal section of the chest and part of thecylinder on liney y in Fig. 1. Fig. 6 is an enlarged view of theeccentric-arm, rocker-arm, and latch. Fig. 7 is an enlarged longitudinalsection of one of the balanced valves in section on line y y in Fig. 1.Fig. 8 is a sectional view of the same on line 2 z in 7, and Fig. 9 is aview of part of the chest shown in Fig. 5 with the valve shifted to openthe induction-port.

A is the steam-cylinder, and B the valvechest, the heads being omittedfrom both. The valve-chest is provided with a steam-supply pipe, B,which delivers the steam into a passage, C, from which it is conductedto the opposite ends of the chest through passages C, and thus deliveredto cylindrical seats I), in which are formed annular cylinder inductionand eduction ports 6. At the middle of the chest, in line with the seatsD, are formed two dash-pots or compression-chambers, f, furnished eachwith a steam-inlet, g, at some distance from their dividing-partition h.

Intermediate to the seats D and chambers f exhaust-apertures i areformed in one side of the chest adjacent to the cylinder A, andconnected by passages J with the exhaustnozzle K upon one side of thecylinder A. Two piston-valves are fitted to the chest, each consistingin a steam-cut-ofl' piston, Z, and a compression or dash-pot piston, Z,connected by a cylindrical shank, which is shown formed with annularteeth m, to constitute a rack for the application of a segment, or, toshift the I valve. Each segment is secured to a separate rock-shaft, 0,and the annular teeth at permit the valve-pistons-to turn in theirseats, and thus equalize the wear.

The rock-shaft may be oscillated by any suitable cutoff mechanismadapted to open the valve during the required part of the stroke and tothenrelease it, after which the compression of the steam in the dash-potf operates to shift it automatically and close the steam-cylinder port6.

The piston Z is the true valve which opens and closes the port 6, whichserves both for vnduction and eduction, and when set outside IOC whenthe piston Z is central over the port, as

shown in the same iigure.

The steam in the dash-ptiuf is therefore unable toescapc when the pistonZ is moved by the cutoff mechanism to open the induction-port, anddevelops by compression a resistance upon the piston Z, which operates,

when the cut-off mechanism releases the' valve, to immediately throw thepiston 7 over the port 0 and close it, as desired. 13y forming the seatD and piston l a little larger than the piston Z the pressure upon thepiston Z is or may be made greater than that upon the piston l, aml assoon as the piston 1 passes the steam-inlet g, when moved automaticallyby the steam compressed in the chamber f, the difference of live-steampressure upon the piston 7 becomes operative and arrests the movement ofthe valve and holds it normallyin its central position. (Shown in Fig.

The operation oi' the piston Z in the chambcrfisthe same as that of theplungerin any form of dash-pot, and permits the free movement of thepiston or valve Z until the piston or plunger I passes over the hole g.The steam in the dash-pot then becomes compressed and serves to returnthe valve to its central position as soon as it is tripped by thecut-oil. mechanisn'i, which will be hereinafter described. It thecompressed steam in the dash-pot possessed too high a tension when thevalve was tripped, it might throw the valve over the port c with toogreat force or velocity, and thus open the exhaust. To check themovenuznt of the valve when thrown to its middle position is the objectof making the piston l a. little larger than the plunger Z, so that whenthe live steam presses upon both the difference of. pressure willoperate to arrest the moving valve; but I have also provided a means toprevent any excess of pressure in the dash-potj", and thus regulate thevelocity of the valves returi'i movement within the required limits.Such means consists in a relief-valve, n opening from the chamberf i ntothe li ve-steam space, and held to its seat by a regulated spring, a soas to open when the pressure of the steam compressed in the dash-potexceeds a certain amount. By making the pistons l and 1 to vary in areaone square inch and giving the relief-valve a an area of one inch it isobvious that the pressure operative upon the piston l to oppose thevalve 1 to its neutral position would never exceed the actual tension ofthe spring '11", as the valve u" would be opened when such tension wasexceeded by eon'i 'iression in the dash-pot.

The means shown [or moving the valves and tripping the same whensupplying steam to the ports 6 is shown herein similar to that used incertain Corliss-valve steam-engines; but a peculiar modification is madeto enable the same mechanism to actuate the same valves during theexhaust ot' the steam from the same port,

Each valve is connected by the toothed segment a positively with itsrock-shaft 0; but such shaft is unlike the rock-shaft:- of Corlissvalves in general clutched to the eccentricrod of the engine during theexhaust half of each stroke, and is thus moved positively ontward fromthe dash-pot during the first half of the exhaust-stroke to connect theport e with the exhaust-aperturc 2 and positively inward during the lasthalf of the exhauststroke to close the port 6 and set the valve inreadiness to take steam at the beginning of the working stroke of the engine-piston. Such clutching mechanism consists partly of the cut-offlatch and partly of a dog or key on the rock-shaft, arranged to engagewith the cocentric-arm just at the time the latch is caught, but in anopposite direction, so that the dog and latch together hold therock-shaft i from turning in either direction, and connect it positivelywith the eccentric rod or arm. The dog, like the latch, engages with thesh ai't when moved in only one direction and affords a free movement inthe opposite direction, and the rock-shaft is thus free to turn backwardwhen the cut-off latch is tripped to per mit the dash-pot to shift thevalve, as desired, to cut off the steam.

The operation of these devices is shown in Figs. 1, 2, 3, and (5, abeing the cut-cit latch, P the eccentric-rod, P the eccentric-armsapplied to turn loosely upon the rock-shafts o, and b the catch upon thearm P ,With which the latch a engages, Each latch. is pivoted to acrank-arm, 0, attached rigidly to the end of the shaft 0, and the valveZ is thus moved with. the latch a whenever the latter is aetuated. DisksE are pivoted upon the shafts 0, and are formed upon their peripherieswith raised seats s, to detach the latches a from the catches bat theproper point in the steamstroke, and rollers c are provided upon theouter ends of the latches to operate withsuch raised seats, as is commonin Corliss engines. Springs o. press the rolls upon the disks. The disksE are properly linked together by a bar, I, and are held in the requiredposition to trip the cntoti' latches a by a rod, 1, which would beactuated by a suitable governor.

The dog is shown as a key, '1', fixed in the shaft 0, and operatii'ig ina wide keyway, r, formed in the hub of the eccentric-arm P, to permitlost motion in one direction, as per arrow i in Fig. 6, when the latcha. is tripped.

The arms P are moved regularlyback and forth by the eccentric-rod 1,(being connected by a link, P and the wide keyway aiiords a looseconnection in one direction between the arm P and the crank c, carryingthe latch, to

ITO

permit the backward movement of the latch, as per arrow 6, and thevalve-piston Z, when actuated by the pressure in the dash-pot f, whilethe rod P is moving in the opposite direction, as per arrow it. On thereturn-stroke of the rod P, when it is moved as per arrow u in Fig. 6,the valve is held in its neutral position by the pressure upon thepistons Z and Z, as shown in Fig. 4-, until the arm P reaches its middleposition, (shown in Fig. 6,) the keyway r turning freely over the keywayr in the shaft 0 until the side of the kcyway strikes the edge of thekey. The latch a engages the catch 1') at the same time as the keyengages the side of the keyway, and the crank c is then looked to thearm P in both directions. The valve thereafter moves in unison with theeccentric-rod, and the piston lis carried back and forth during theexhaust-stroke of the engine working-piston the same as a plainslide-valve The valve also opens to supply steam to the working-pistonunder the control of the arm P, and moves in unison with theeccentric-rod P until the latch a is tripped by the seat 8.

From the above description it Will be seen that I have devised a valvewhich is as readily tripped for cutting off the steam as any Corlissvalve, but, unlike any Corliss valve, is moved positively to open theexhaust, and by the same latch and eccentric-arm also. I thus make twovalves operate as effectively as the four valves ordinarily used inCorliss engines, and secure the same free exhaustand the same facilityfor regulation. It is obviously immaterial how the dog operates toengage the eccentric-arm P upon the side opposite to the latch a, andinstead of the key 0' and wide kcyway r a circular plate may be attachedto the shaft o'and slotted to fit a pin projected from the side of thearm P. The slot in such case would permit the play in one direction thesame as the wide keyway r, while the pin could strike the end of theslot with the same effect as the key r operates. 1

It is also immaterial, so long as balanced 1i)lStOl1\'1lVPS are used,whether the dash-pot be located inside the valve-chest or not, as it isalready common to attach the dash-pot plunger for closing the cut-offvalve to the 1 r sage intermediate to each of the said comcrank-arm c,that carries the latch (1.

Having thus set forth my invention, what I I claim herein is 1. Acylindrical valve having one end ap plied to an annular cylinderinduction-port and the other end fitted to a compressionchamber providedwith a steam-inlet in its side to introduce the steam under pressure,and the induction-port and the steam-inlet being arranged in relation tothe valve so that the steam-inlet is closed as the induction-port isopened, as and for the purpose set forth.

2. A cylindrical valve having one end applied to an annular cylinderinduction-port, an opposite end of smaller diameter fitted to acompression-chamber provided with a steaminlet in its side, a rock-shaftfor shifting the valve to open the induction-port and compress the steamin the compression-chamber, and cut-off mechanism to release suchrockshaft at a suitable point, substantially as herein set forth.

3. A cylindrical valve having one end applied to an annular cylinderinduction-port and the other end fitted to a compressionchamber providedwith a steam-inlet in its side to introduce the steam under pressure,and the induction-port and the steam-inlet being arranged in relation tothe valve so that the steam-inlet is closed as the induction-port isopened, and an outlet-valve from the 001111)IQSSlOil OhfilllbBl to limitthe pressure therein, as and for the purpose set forth.

4. A cylindrical valve having one end applied to an annular cylinderinduction-port and the other end fitted to a compressionchamber providedwith a steam-inlet in its side to introduce the steam under pressure,and the induction-port and the steam-inlet being arranged in relation tothe valve so that the steam-inlet is closed as the induction-port isopened, a passage leading from the compression-chamber through thepistonvalve, and a relief-valve seated upon the outer side of suchpassage, as and for the purpose set forth.

5. The combination, with a steam-cylinder valve-chest, of twocylindrical compressionchambers in the middle of the chest withsteam-inlets in their sides, two cylindrical valve-seats with annularinductiolrports near the ends of the chest, a steam-supply to suchvalve-seats and steam-inlets, an exhaust-passage intermediate to each ofthe said compression-chambers and valve-seats, and two valves providedat their opposite ends with pistons fitted, respectively, to suchchambers and valve-seats, the whole arranged and operated substantiallyas herein set forth.

6. The combination, with a steam-cylinder 'alve-chest, of twocylindricalcompressionchambers in the middle of the chest, withsteam-inlets in their-sides, two cylindrical valve-seats with annularinduction-ports near the ends of the chest, a steam-supply to suchvalve-seats and steam-inlets, an exhaust-paspressionchambers andvalve-seats, two valves provided each with pistons at their oppositeends, and with an intermediate shank having a rack formed thereon, androck-shafts provided with segments to reciprocate such valves, andcut-off mechanism for actuating such rock-shafts, substantially asherein set forth.

7 In a steam-engine, the combination, with a port operating as aninduction and eduction port, of a piston-valve fitted thereto andconnected with a rock-shaft, an eccentric-arm fitted loosely upon saidshaft, a dog to engage the arm in one direction and a crank-arm attachedto the shaft and provided with a latch to engage the arm in the oppositedirection, i In testimony whereof I have hereunte sei; and mechanism fort-rippingthe latch, as and n1 y hand in the presence of two subscribingT0 for the purpose set forth. Witnesses. V

8. In a Steam-engine,theconlbinntion,with i VWILBUR 3L rHITI-OCK 5 abalanced nston-valve, of: a steam dash-pot and a relief-valvedischarging from the interior 01 such dash-p01; into the steam-space ofvalve-chest, as and fur the purpose set forth.

\Y i t nessesr THos. S. CRANE,

i F. FISCHER.

